Valve



P. L. SCOTT Nov. 6, 1934.

VALVE Filed Oct. 20, 1930 I72 "06 72 LL07 fz'zzjy [0026 5006a QAL Patented Nov. 6, 1934 VALVE Philip Lane Scott, San Mateo, Calif., assignor to Super Diesel Tractor Corporation,

La Porte,

Ind., a corporation of New York Application October 20,

' -1 Claim.

This invention relates to a combination of metals and the process of combining them.

It has for one object to provide an apparatus in which extremely hard parts are carried by 5 and-to some extent reinforced by tougher and less hard parts.

Another object of the invention is to provide an extremely hard seating part in a member tougher, less hard and for certain purposes more yielding.

Another object is to provide in a tough and yielding member a much harder, unyielding part.

Another object is to provide about a hard metal part a tougher metal part which surrounds, supports and compresses the harder part.

Another object of the invention is to provide aprocess for forming, uniting and assembling the parts and members above mentionedand for providing a construction in which a relatively compression, in a tougher material and in which the hardness and the compression is caused by treatment after assembly.

Other objects will appear from time to time in the course of the specification and claim.

My invention is illustrated more or less diagrammatically in the accompanying drawing, wherein- Figure 1 is a vertical cross section, a perforated disc and needle point closing the perforation;

Figure 2 is a plan view of a disc;

Figure 3 is a cross section taken at line of Figure 2.

Like parts are designated by like characters throughout the specification and drawing.

A is a disc provided with a perforation A and araised boss A The boss A has an enlarged cavity A formed within it. The cavity A communicates with and forms in efiect a continuation of the perforation A The disc is preferably formed ,of chrome nickel steel. It is capable of heat treatment and when so treated may be held in the austenitic state.

B is a seat plug member formed with a reduced portion B which is adapted to lie within the perforation A of the disc. B is a perforation through the seat plug. The seat plug is preferably made of a material which may be hardened and during treatment acquires a hard case B It is made preferably of low carbon steel with high aluminum content.

. C is a needle point or valve member. It is modified form of formed preferably with a cavity C and is prefbrittle and hard material is supported, under 1930, Serial No. 489,736

erably made of chrome nickel steel similar to or identical with the disc A.

D is a needle point member positioned within the cavity C and preferably sharpened at its exposed end or point as at D It is preferably 9 made of the same sort of material as the seat plug B, and as the case D In Figures 2 and 3 a. modified form is shown which differs from the form shown in Figure 1 in details of design and construction but is 5 preferably the same in materials used and in the manner in which they are treated.

E is a disc provided with a perforation E and having a raised boss E which is hollowed out to provide a cavity E which communicates with 7 the perforation E. I

I F is a seat plug perforated as at F and seated within the cavity E. This disc may be used with a needle point similar to that shown in Figure 1.

The manner in which the parts are assembled and formed is as follows:'

The disc and the main needle parts are preferably made of high chrome nickel steel which may be held in the austenitic state by heat treatment,

and the seat plug and needle point plug are preferably made of low carbon steel, having a relatively high aluminum content. The relatively soft seat plug or needle point is inserted in the disc or needle which is formed of a tough material which is of such construction and nature that 5 it will not be appreciably affected by nitrogen or by any nitriding process. With the parts thus assembled they are treated with nitrogen. In one example, they are subjected tonitrogen at a temperature of approximately 900 F. This heat 9 treatment may be carried on for about four hours. After this treatment, the austenitic steel retains is strength but the relatively softer seat plug or needle point member will absorb nitrogen and become gradually very hard. It will also swell in p 5 size somewhat, the amount of swelling depending upon the time of heat treatment with the hot nitrogen. In the four hour treament a case of approximately .003 inch in thickness is formed on the nitrided parts.

The seat plugs and the needle points formed in this fashion are extremely hard and they are under compression which may beas high as the material permits and is controlled largely by the a length of time of the treatment. 1 5

If now such needle points and seat plugs are used together, because of their great hardness the efiect of wear is reduced to a minimum. If fracture takes place in the heart of the material the 1 pieces are so tightly held together by the com- 110 of parts.

While I have illustrated the use of my process and my device in connection with a disc valve of a type adaptable for use in furnishing fuel for an internal-combustion engine,'it is obvious that my invention is not limited to this use and it might be applied to any type of valve and, in fact, to any use where it is advantageous to provide an extremely hard part in a relatively tougher surrounding part and my invention is, therefore, not to be considered as limited to its use or application in connection with an internal-combustion engine valve or a valve of any sort. a

As mentioned above the swelling of the nitridable member within the non-nitridable member occurs in response to the nitriding treatment and the amount of the swelling is controlled to some degree by the extent of the nitriding action. Thus the amount of expansion or swelling can be controlled in part by controlling the extent of the nitriding action and under some conditions it can conveniently be done by controlling the amount 01' time during which the member is subjected to nitriding treatment. t

By reason of the swelling or expanding caused by the nitriding treatment the parts may initially be made without very close fits and undue strain as the result of the imperfect fits in the finished product may be largely avoided and it is ordinarily necessary only to know the closeness of the fit to fix the extent to which the'nitriding process should be carried out.

I claim:

In combination in a valve assembly, a seat carrying member formed of chrome nickel steel, and a seat member supported therein and formed of aluminum steel, 'a valve closing member formed of aluminum steel and a carrying part therefor, formed of chromium nickel steel, the parts being assembled and subsequently nitrided, whereby the seat member and the closing member are provided with a nitrided case of extreme hardness and are further caused to expand within their respective holding parts.

PHILIP LANE SCO'I'I. 

